[gcc r14-10487] Compare loop bounds in ipa-icf

[Jan Hubicka via Gcc-cvs]

https://gcc.gnu.org/g:c5397d343ff1365fcebcf3ebabe140608874aac3

commit r14-10487-gc5397d343ff1365fcebcf3ebabe140608874aac3
Author: Jan Hubicka <hubi...@ucw.cz>
Date:   Mon Jul 22 18:01:57 2024 +0200

    Compare loop bounds in ipa-icf
    
    Hi,
    this testcase shows another poblem with missing comparators for metadata
    in ICF. With value ranges available to loop optimizations during early
    opts we can estimate number of iterations based on guarding condition that
    can be split away by the fnsplit pass. This patch disables ICF when
    number of iteraitons does not match.
    
    Bootstrapped/regtesed x86_64-linux, will commit it shortly
    
    gcc/ChangeLog:
    
            PR ipa/115277
            * ipa-icf-gimple.cc (func_checker::compare_loops): compare loop
            bounds.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.c-torture/compile/pr115277.c: New test.
    
    (cherry picked from commit 0d19fbc7b0760ce665fa6a88cd40cfa0311358d7)

Diff:
---
 gcc/ipa-icf-gimple.cc                          |  4 ++++
 gcc/testsuite/gcc.c-torture/compile/pr115277.c | 28 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/gcc/ipa-icf-gimple.cc b/gcc/ipa-icf-gimple.cc
index c25eb24710f6..4c3174b68b67 100644
--- a/gcc/ipa-icf-gimple.cc
+++ b/gcc/ipa-icf-gimple.cc
@@ -543,6 +543,10 @@ func_checker::compare_loops (basic_block bb1, basic_block 
bb2)
     return return_false_with_msg ("unroll");
   if (!compare_variable_decl (l1->simduid, l2->simduid))
     return return_false_with_msg ("simduid");
+  if ((l1->any_upper_bound != l2->any_upper_bound)
+      || (l1->any_upper_bound
+         && (l1->nb_iterations_upper_bound != l2->nb_iterations_upper_bound)))
+    return return_false_with_msg ("nb_iterations_upper_bound");
 
   return true;
 }
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr115277.c 
b/gcc/testsuite/gcc.c-torture/compile/pr115277.c
new file mode 100644
index 000000000000..27449eb254f8
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr115277.c
@@ -0,0 +1,28 @@
+int array[1000];
+void
+test (int a)
+{
+        if (__builtin_expect (a > 3, 1))
+                return;
+        for (int i = 0; i < a; i++)
+                array[i]=i;
+}
+void
+test2 (int a)
+{
+        if (__builtin_expect (a > 10, 1))
+                return;
+        for (int i = 0; i < a; i++)
+                array[i]=i;
+}
+int
+main()
+{
+        test(1);
+        test(2);
+        test(3);
+        test2(10);
+        if (array[9] != 9)
+                __builtin_abort ();
+        return 0;
+}